One significant outgrowth that has resulted from the prolific use of personal computers to generate documents, coupled with the increasing resolution of printers, is the wide variety of fonts that are available to the average user. In the past, a relatively small number of fonts were typically employed by most users. The most common fonts were usually stored on the users' computers, for example in connection with word processing programs, and likewise stored in the memories of printers. As a result, if a document was created with the commonly employed fonts and subsequently transmitted to another user's computer, there was a high likelihood that the document could be viewed and printed at the remote user's site, since the necessary information relating to the generation of the font's characters and symbols would be available at that site.
More recently, a large number of different types of fonts have become readily available, to provide users with the ability to create different appearances for documents, and thereby present information in a highly attractive manner. To this end, various specialized fonts enable users to employ characters in new and different ways. For example, the "pi" font set (a collection of symbol characters) contains a number of unique symbols that can be used to emphasize messages and create particularly attractive documents. One problem associated with the use of numerous varied fonts is the fact that data which describes the characters of a given font may not be stored on all computers and/or printers. If a document containing characters from such a font is transmitted to a computer which does not contain the data for the font, the user at that computer is not able to view or print the document with all of the information that was intended by the document's author.
To alleviate this situation, certain types of document formats include font information with the contents of the document itself. One example of such a format is the PDF file format, in which the resources for every font that is employed in a document are stored as part of the document file. This approach is particularly advantageous in the case of documents which use special character fonts, such as the pi font. However, the incorporation of font resource information into the document file significantly increases the overall size of the file. This drawback is particularly exacerbated if the document employs fonts with large character sets, such as those associated with the Japanese and Chinese languages. For example, a non-compressed character set for Kanji characters may contain 3-8 MB of data.
It can be appreciated that the transmission of documents whose files incorporate font resources can require a significant amount of time. Likewise, a significant amount of memory can be required to store such files. If multiple fonts are employed in a document, the size of the document file, and hence the transmission time and memory requirements, increase in a commensurate manner. Accordingly, it is desirable to provide a system in which font resources can be made available to users so that documents can be viewed and printed in their original form at any site, but which eliminates the need to transmit the font resource along with the contents of the document.